Saturday, August 06, 2005

The twenty-minute workday

Continuing my calculated assault on the well-intentioned but mistaken Frenchman Pierre Chomat, I decided to put his "one gram of oil = one human workday" claim to the test. He defined the work a person can do in a day as lifting 2000 kg of sand up 2 meters (6 ft 6 inches). Not having 2 kg of sand, I instead used a 5-kg dumbbell. I proceeded to lift it from the ground to over my head, a distance of approximately 6 feet 3 inches, 440 times. Allowing for the possibility that I didn't put it all the way down or lift it all the way up a few times, I called it six feet even, or 1.846 meters. This worked out to almost exactly the same amount of work as he calculated using a shovel: 2000 * 2 * 9.81 = 5 * 440 * 1.846 * 9.81. In Chomat's book, he claims that it would take a hard-working human all day to do this amount of work. I did it in 20 minutes and 29 seconds. That works out to an average of only 32.4 watts. Given a better mechanism for doing the work, like a pedal drive, I can easily put out five times that much power.